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Calculate your estimated one repetition maximum (1RM) for weightlifting
Execution
Fill in the form, run the tool, and review the result in one place.
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Tool usage guide
The One Rep Max (1RM) Calculator helps weightlifters and athletes estimate their maximum strength capacity for a single repetition based on submaximal lifting performance. By inputting the weight lifted and the number of repetitions performed, you can accurately gauge your progress and structure your training intensity without the physical strain of attempting a true one-rep maximum lift.
Background
A lifter wants to know if their recent 80kg bench press for 8 reps indicates progress toward their 100kg goal.
Problem
Needs to estimate current 1RM to adjust training volume.
How to use
Input 80kg, 8 reps, and select the Epley formula.
weight: 80, reps: 8, formula: epleyOutcome
The calculator estimates a 1RM of approximately 101kg, confirming the lifter has surpassed their goal.
Background
A trainee is starting a new program that requires squats at 75% of their 1RM.
Problem
Does not know their current 1RM to calculate the 75% load.
How to use
Input the weight and reps from their last successful set of 5 reps at 100kg.
weight: 100, reps: 5, formula: brzyckiOutcome
A One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition of a specific exercise with proper form.
Calculating your 1RM reduces the risk of injury associated with lifting maximal loads and allows you to estimate strength capacity during regular training sessions.
Epley is widely used for general strength, Brzycki is often preferred for its simplicity, and Lander is frequently used for heavier loads; all provide reliable estimates.
It is most accurate for compound movements like squats, deadlifts, and bench presses, but accuracy decreases as the number of repetitions increases beyond 10.
Yes, provided you add external weight (like a dip belt) to your bodyweight to reach a failure point within a low repetition range.
The tool provides an estimated 1RM of 112.5kg, allowing the user to calculate their 75% working weight as 84.4kg.